Do your research first regarding what a tuxedo should actually entail. The vast majority of tuxedos out there are not at all correct in their style or materials. A tuxedo is not a suit jacket with satin lapels.
Blacktieguide.com is a decent start. I actually got my tux from Indochino a few years ago. They, like black lapel and other made to measure companies, allow you to customize your tux so that it is correct and does not look like an abomination like what most men end up wearing to weddings and formal functions.
I really like how mine turned out, and the quality is reasonably good, and exceptional given the price. Particularly for something I will not be wearing too frequently, I was much more interested in getting the style, materials, and fit correct then worrying as much about quality of construction. Then again, I am somewhat of an odd shaped human being, so it is difficult to find off the rack suits and tuxes that fit.